Colorectal cancer (CRC) is the 2nd leading cause of cancer deaths in the US and risk increases with age. Colorectal cancer screening (CRCS) offers the possibility of both early detection and prevention. For those at average risk, CRCS beginning at age 50 is recommended. However, awareness and use of CRCS tests are low. We propose to conduct a randomized controlled trial to develop and test stepped interventions to increase initial uptake of CRCS in a nationally-representative, ethnically-diverse sample of male and female veterans. Our specific aims are to: (1) develop and pre-test stepped intervention components that are theory- and evidence-informed;(2) implement and evaluate the process, efficacy, and cost-effectiveness of stepped interventions to increase an initial CRCS among male and female veterans aged 50-64 years;and (3) analyze the association between predictor variables and CRCS initiation and the mediating and moderating effects of the interventions, after each step. In Step 1, we will evaluate a theory-based minimal cue delivered by a letter, telephone call, or automated telephone call compared with a survey-only control group to determine whether the 3 different delivery channels are equally efficacious and cost-effective. Minimal cues are a cost-effective method that prompts to action those more willing to change and are easy to disseminate in real-world settings. Persons who do not complete CRCS in Step 1 will be randomized in Step 2 to more intensive interventions that address resistance. In Step 2 we will determine whether a theory-based, tailored telephone intervention, using principles of Motivation Interviewing, is effective when delivered as part of a sequential intervention process in which early adopters have been removed from the population. Step 2 also will determine whether an automated approach, telephone-linked communication (TLC), is as effective as a telephone counselor in promoting initiation of CRCS. Steps 1 and 2 together will address the important issue of the "dose" needed to encourage completion of CRCS. After each step, we will examine the mediating and moderating effects of the intervention to identify determinants of completion. For cancer screening intervention research to have the broadest public health impact, interventions must have the potential for dissemination. We designed our trial to move us toward the goal of disseminable interventions with evidence of external validity.